Development of an interface apparatus combining a projector with a camera has been under way in recent years. Such an interface apparatus provides an interactive operation by detecting, with a camera, a manipulation performed on an image projected from a projector. NPL 1 discloses an interface apparatus combining a projector with a camera.
When a phase modulation type spatial modulation element is used in a projector in an interface apparatus, a phase distribution related to a displayed image is displayed on a display surface of the spatial modulation element. A desired displayed image can be displayed on a projection surface by projecting reflected light of light irradiated on the display surface of the spatial modulation element. A phase distribution displayed on the spatial modulation element is formed one by one by using arithmetic processing such as an iterative Fourier transform method. Accordingly, an amount of calculation may become enormous and may cause delay in the processing when a projection environment is changed or a dynamic image is displayed.
PTL 1 discloses a dynamic image hologram display device enabling generation and reproduced display of a dynamic image hologram. The device in PTL 1 enables to generate an interference fringe of a target object after a specific time period, without recalculating a hologram, and therefore enables to provide high speed hologram calculation, and generation and reproduced display of a dynamic image hologram in real time.
Normally, in order to display basic figures such as a circle and a rectangle at a plurality of positions, a phase distribution related to a displayed image in which a basic figure is arranged at each position needs to be prepared. In a simple pattern, a basic figure can be moved to any position by performing a shift operation on a phase distribution related to the basic figure. Accordingly, by preparing one phase distribution related to a basic figure, the basic figure can be displayed at any position by performing a shift operation on the phase distribution. Thus, assuming that a shift operation is performed, a storage capacity on the device side can be reduced. Meanwhile, when a shift operation is performed on a phase distribution related to a basic figure, a part other than the basic figure may look as though the part is studded with optical noise in a displayed image projected by using the phase distribution, and contrast may be reduced.
NPL 2 discloses a method of improving contrast of a displayed image by setting a signal region aiming at convergence of a light intensity to a target pattern and setting a range provided with a degree of freedom except for the signal region, when performing an iterative Fourier operation.